1. Field
The present embodiments relate generally to toilet flush valves and particularly to refill for dual flush valves.
2. Description of Prior Art and Related Information
A toilet tank typically employs a flush valve that is forced open, which remains open until a predetermined amount of water flows from the tank into the toilet bowl through the flush valve. A fill valve provides water from a supply line to the toilet tank. The fill valve is open whenever the water level in the tank is below a predetermined level.
In a dual flush valve toilet assembly, a toilet bowl is normally refilled during the time the toilet tank is filled up by water from a fill valve. The amount of water used to refill a toilet bowl must be enough to seal off the trap way of the howl. This amount usually is determined as a percentage of the total flow volume of a fill valve during a flush cycle. This water is tapped from a port of a fill valve and fed to the tank bowl through a flexible tube, running down an overflow tube of a flush valve. There are two scenarios when a dual flush is used in a toilet to flush water from the tank to the bowl.
First, the refill amount is set so that for a full flush, water is refilled just enough to seal off the trap way of the bowl. However, for a half flush, when it only takes about a half of the time to fill up the tank compared to a full flush, refilled water is not enough to seal off the trap way. This will create three problems for the bowl: dirty bowl for the next usage, sewage gas escaped from the trap way, and a bad flush on the next usage.
Second, the refill amount is set higher so that a half flush can have enough water to refill the bowl to seal off the trap way. However, for a full flush, because of its double filling time, more water will be wasted and the total flow volume for a full flush may not meet code requirements.